1. Field
Exemplary embodiments of the present invention relate to a semiconductor design technology, and more particularly, to a differential amplifier circuit for a low drop-out (LDO) voltage regulator.
2. Description of the Related Art
An electronic circuit includes an amplifier for amplifying a signal so that the signal is much greater than noise. In particular, the amplifier may be implemented using a differential amplifier for receiving differential input signals, performing a comparison between the differential input signals, amplifying the results of the comparison, and outputting an output signal. Accordingly, the differential amplifier is one of the most important elements forming the circuit, and the entire circuit performance may depend on the performance of the differential amplifier. Research is carried out on a differential amplifier of low power consumption because all of the recently developed electronic circuits are aimed at a fast operation for user needs and low power consumption.
A device for supplying stable power regardless of output impedance is called a voltage regulator. In particular, a regulator having a relatively small difference between an input voltage and an output voltage is called a low drop-out (LDO) voltage regulator. Such an LDO voltage regulator requires a differential amplifier characterized in that it can rapidly recover an output voltage when the output voltage is changed due to an instant change of a load current.